KIT and neoplasm: Multivariable prognostic factor analysis performed to assess the impact of the different baseline covariates on PFS and OS, showed that the absence of KIT Exon 11 del or delins 557/558, the female gender, a primitive tumor diameter ≤5 cm and PMN leucocytosis (>7.5 × 109/L) were significant prognostic factors for longer PFS to first-line imatinib; only performance status remains statistically significant in the multivariate model for OS.